I'm trying to use the python Xlib library and am running into the issue that Xlib functions do not seem to work when inside a function that I define and then import.
For example, if I take the example program that comes with Python Xlib, childwin.py, and simply put it inside a function in a file named childtest.py as follows:
#Python 2/3 compatibility.
from __future__ import print_function
import sys
import os
# Change path so we find Xlib
def xlib_test():
print('Running xlib_test()')
sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
from Xlib import X, display, Xutil
# Application window
class Window(object):
def __init__(self, display):
self.d = display
# Find which screen to open the window on
self.screen = self.d.screen()
# background pattern
bgsize = 20
bgpm = self.screen.root.create_pixmap(
bgsize,
bgsize,
self.screen.root_depth
)
bggc = self.screen.root.create_gc(
foreground=self.screen.black_pixel,
background=self.screen.black_pixel
)
bgpm.fill_rectangle(bggc, 0, 0, bgsize, bgsize)
bggc.change(foreground=self.screen.white_pixel)
bgpm.arc(bggc, -bgsize // 2, 0, bgsize, bgsize, 0, 360 * 64)
bgpm.arc(bggc, bgsize // 2, 0, bgsize, bgsize, 0, 360 * 64)
bgpm.arc(bggc, 0, -bgsize // 2, bgsize, bgsize, 0, 360 * 64)
bgpm.arc(bggc, 0, bgsize // 2, bgsize, bgsize, 0, 360 * 64)
# Actual window
self.window = self.screen.root.create_window(
100, 100, 400, 300, 0,
self.screen.root_depth,
X.InputOutput,
X.CopyFromParent,
# special attribute values
background_pixmap=bgpm,
event_mask=(
X.StructureNotifyMask |
X.ButtonReleaseMask
),
colormap=X.CopyFromParent
)
# Set some WM info
self.WM_DELETE_WINDOW = self.d.intern_atom('WM_DELETE_WINDOW')
self.WM_PROTOCOLS = self.d.intern_atom('WM_PROTOCOLS')
self.window.set_wm_name('Xlib example: childwin.py')
self.window.set_wm_icon_name('childwin.py')
self.window.set_wm_class('childwin', 'XlibExample')
self.window.set_wm_protocols([self.WM_DELETE_WINDOW])
self.window.set_wm_hints(
flags=Xutil.StateHint,
initial_state=Xutil.NormalState
)
self.window.set_wm_normal_hints(
flags=(Xutil.PPosition | Xutil.PSize | Xutil.PMinSize),
min_width=50,
min_height=50
)
# Map the window, making it visible
self.window.map()
# Child window
(self.childWidth, self.childHeight) = (20, 20)
self.childWindow = self.window.create_window(
20, 20, self.childWidth, self.childHeight, 0,
self.screen.root_depth,
X.CopyFromParent,
X.CopyFromParent,
# special attribute values
background_pixel=self.screen.white_pixel,
colormap=X.CopyFromParent,
)
self.childWindow.map()
# Main loop, handling events
def loop(self):
current = None
while 1:
e = self.d.next_event()
# Window has been destroyed, quit
if e.type == X.DestroyNotify:
sys.exit(0)
# Button released, add or subtract
elif e.type == X.ButtonRelease:
if e.detail == 1:
print("Moving child window.")
self.childWindow.configure(
x=e.event_x - self.childWidth // 2,
y=e.event_y - self.childHeight // 2
)
self.d.flush()
# Somebody wants to tell us something
elif e.type == X.ClientMessage:
if e.client_type == self.WM_PROTOCOLS:
fmt, data = e.data
if fmt == 32 and data[0] == self.WM_DELETE_WINDOW:
sys.exit(0)
if __name__ == '__main__':
Window(display.Display()).loop()
xlib_test()
because of the last line xlib_test(), if I run this file by typing
python childtest.py
in the terminal, the program works and a window appears. If however I open a python interpreter, import the function and then run it,
from childtest import xlib_test
xlib_test()
No window shows up, so that Xlib functions seemingly do not work. Is anyone able to explain this behavior and how I can correct my setup to work around it? My goal is to write my Xlib functions in a separate file and import those functions in my main code.
It's normal, it's because of this line:
if __name__ == '__main__':